Output formatting basics in Java - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of System.out.printf() in Java?

It is used to print formatted output to the console, allowing you to control how variables and text appear, such as setting decimal places or alignment.

beginner

How do you format a floating-point number to show 2 decimal places using printf?

Use %.2f in the format string. For example: System.out.printf("%.2f", 3.14159); prints 3.14.

beginner

What does the format specifier %d represent in Java's printf?

It represents a decimal integer. It is used to format integer values in the output.

intermediate

How can you align text to the right in Java's printf?

By specifying a width in the format specifier, like %10s, which right-aligns the string in a field 10 characters wide.

beginner

What is the difference between System.out.print() and System.out.println()?

print() outputs text without moving to a new line, while println() outputs text and then moves the cursor to the next line.

Which format specifier would you use to print a floating-point number with 3 decimal places?

A %s

B %.3f

C %d

D %.3d

The specifier %.3f formats a floating-point number to 3 decimal places.

What does System.out.printf("%10s", "Hi") do?

A Prints 'Hi' right-aligned in a 10-character wide space

B Prints 'Hi' left-aligned in a 10-character wide space

C Prints 'Hi' with 10 spaces after it

D Prints 'Hi' with 10 spaces before and after

The %10s specifier right-aligns the string in a field 10 characters wide.

Which method prints text and moves to a new line automatically?

A System.out.print()

B System.out.printf()

C System.out.println()

D System.out.write()

println() prints text and then moves the cursor to the next line.

How would you format an integer variable named num in printf?

A System.out.printf("%c", num);

B System.out.printf("%f", num);

C System.out.printf("%s", num);

D System.out.printf("%d", num);

%d is used to format integers in printf.

What will System.out.printf("%.1f", 2.78); output?

A 2.8

B 2.7

C 2.78

D 3.0

It rounds the number to 1 decimal place, so 2.78 becomes 2.8.

Explain how to use System.out.printf to format a number with two decimal places and right-align it in a 10-character wide field.

Think about combining width and precision in the format string.

Describe the difference between print, println, and printf in Java output.

Consider how each method handles text and line breaks.